The present invention relates to a method and a device for controlling a setting element in a vehicle.
In vehicles, electrically operable setting elements are increasingly used that are driven so as to influence at least one performance quantity of the vehicle. In the context of the safety monitoring of control systems of this type, active tests are known in which the setting element is actively driven in response to the onset of a predefined operating condition, in order to deduce from its reaction or from the reaction of at least one operating quantity influenced by it a malfunctioning of the setting element, its components, its electronic control system, etc. As an example, for the engine control system, the active test of a setting element for adjusting the air supply to an internal combustion engine can be cited, the test being depicted, for example, in German Published Patent Application No. 34 35 465 (corresponding to U.S. Pat. No. 4,601,199). With respect to a wheel brake control system, an active test of this type is described, e.g., in German Published Patent Application No. 198 07 367. These tests can also be executed as so-called pre-drive checks, i.e., for test purposes, the active operation of the setting element takes place before the actual commencement of travel, for example, in response to the turning of the ignition key or in response to the presence of other enabling conditions.
These enabling conditions are not in every case plausible for those who are not experts. For example, it is possible to imagine as the enabling condition for an active test the disengaging of the immobilizer or the opening of the vehicle doors. If fitters are working in the area of the electrically controlled setting elements, then the result of activating the test can be motions of the setting elements that are disturbing for them.
Before the beginning of an active test, a person working in the area of the setting element is warned by a defined motion of the electrically controllable setting element about the impending active test. It is especially advantageous that the intensity of the motion of the setting element is dimensioned such that no danger results to this person and yet a clear warning is issued to the person.
One advantageous application is found in all systems in which electrically controllable setting elements are operated both in a controlling function as well as in active tests. Systems of this type are engine control units, electrically controlled brake systems (electrohydraulic, electropneumatic, or electromotor wheel brakes), electrically controlled steering systems, chassis systems having active damping, etc.
The motion of the setting element for warning purposes therefore improves the human-machine interface in active systems. It is particularly advantageous that, by observing the reaction of the setting element to the driving before the activation of the actual active test, it is possible to arrive at conclusions regarding maintenance work in the vehicle. In a case of this type, the designated active test is then advantageously dispensed with.